Charging pump for multicylinder two-stroke combustion engines or compressors



W. STEIGER Aug. 15, 1933.

CHARGING PUMP FOR MULTICYLINDERTWO-STROKE comBusnou ENGINES 0RCOMPRESSORS 2 Sheets-Sheet 1 a 4 .OA U I I|||1 z a h 0 Q m EEE: 9 Wm i Za w. STEIGER 1,922,985

STROKE COMBUSTION ENGINES OR COMPRESSORS Aug. 15, 1933.

CHARGING PUMP FOR MULTICYLINDER TWO 1931 2 Sheets-Sheet 2 Filed Oct. 15

I Viii'ioiizi Patented Aug. 15, 1933 CHARGING PUMP FOR MULTICYLINDERTVVO-STROKE COMBUSTION ENGINES OR COMPRESSORS Walther Steiger, Bern,Switzerland Application October 15, 1931, Serial No. 569,047, and inGermany October 22, 1930 1 Claim.

The present invention relates to charging pumps for multi-cylindertwo-stroke internal combustion engines or compressors and has for itsobject to supply the required quantity of air especially for high speedengines fed with crude oil.

Since a two-stroke crude oil motor needs considerably more air forobtaining a good output than is needed for a two-stroke petrol motor theordinary charging pumps would not suffice and charging devices ofgreater capacity would be required. But such larger devices would haveto be separated from the crank chamber and would require separatedriving and controlling means.

The present invention therefore consists in a two-stroke internalcombustion piston engine provided with a crank case pump and a doubleacting auxiliary pump arranged coaxially with the main cylinder on theother side of the crank shaft so that the piston of this pump will helpwith its inner face to effect the suction and the preliminarycompression of the charge.

The novelty resides in that the machine comprises at least two completeunits consisting of working and pump cylinders displaced at 180 theouter side of each auxiliary pump being in constant open communicationwith the crank case of the said units.

The annexed drawings represent diagrammati cally a wor ing example of afour cylinder plant. There Fig. 1 is a longitudinal section,

Fig. 2 a plan Fig. 3 a cross section and Fig. 4 is a diagrammaticalView.

According to the drawings the cylinders are divided in groups of two.The cylinders 1, 2 and 3, 4 are two such groups. 5, 6, '7 and 8 are theappertaining charging pumps. Not only the cranks of the power pistonsand pump pistons are mutually displaced at 180 but also the cranks ofthe power pistons and the cranks of the two pump pistons. Besides thechambers of the two pump cylinders 5', 6' are communicating mutual- 0 lywith the chambers of the crank chambers 9 and 10 by passageways 5 6opening at the bottom of the pump chambers at 5 6 In a similar way alsothe pistons of the power cylinders 3, 4 and the pump pistons '7, 8 andthe crank chambers 11, 12 are arranged accordingly. The exhaust orifice13 and the inlet orifice 14 of the air are so arranged, that the formeris overlapped by the power piston in its upper dead center and thelatter in the lower dead center position of the piston. Each crankchamber is communicating with the chamber of the power cylinder by anoverflow passageway at opening between the exhaust and the air inlet.

According to this arran ement the working is as follows:

If the piston of the first cylinder of the first group, as seen fromFig. 4 assumes the outer dead center position and the piston of thesecond cylinder assumes the inner dead center position a vacuum isformed between pistons 1 and 5 in the crank case 9 and under the piston6 of the second group and fresh air will fill these chamhere through theunlapped air inlet 14. On the other side the air between pistons 2 and 6and under the piston 5 will be compressed and pressed into the upperchamber of the cylinder 2 through the passageway 15. The crank casecommunicates with the power cylinder through the passageway a, whichalso aiiords communication. between the crank case and the inlet andexhaust orifices. But since also the exhaust orifice 13 is free saidcylinder 2 will have his scavenging or his filling while in the cylinder1 the compression is ready for injecting the fuel and for firing.

Thus the pump pistons are double acting and the dimensions of thechambers are chosen so that these pumps will feed a volume of air whichis a multiple of that of the volume of the power cylinder.

Of course this arrangement of the air pump could also be employed forair compressors.

What I claim is:

In a multi-cylihder two stroke internal combustion engine and incombination with charging pumps, power cylinders arranged in groups ofpairs, a common crankshaft with cranks disr placed in each pair-at 180,pump cylinders one for each power cylinder and juxtaposed to them withregard to said crank shaft, separate crank cases open towards thechambers of each set of power and pump cylinder, passageways mutuallyconnecting in each group the crank cases of one power cylinder to thecompression chamber of the pump of the other cylinder, air inletsarranged so as to be overlapped in the lower dead center position of thepower piston and exhaust orifices r arranged so as to be overlapped inthe upper dead center position of the power piston.

WALTHER STEIGER.

